Dual path web transport and processing apparatus with radiant energy directing means

Abstract

An apparatus and method for processing a sequence of webs by exposure to radiant energy. The apparatus includes structure defining a pair of independent transport paths and apparatus for emitting radiant energy and selectively directing it into either of two treatment zones, the respective treatment zones being aligned with the respective transport paths. The radiant energy is directed into the treatment zone aligned with each transport path while a web is being fed along such path. The leading end of each web is threaded along one of the transport paths while a web is being fed and treated on the other path, so the radiant energy emitting portion of the apparatus is not idle during threading.

What is claimed is: 
     
       1. Web transport and treatment apparatus comprising: (a) a web support structure defining at least two independent web transport paths;   (b) means for emitting radiant energy;   (c) means for selectively directing such radiant energy along at least two separate routes, a first one of said routes extending into a first treatment zone aligned with a first one of said transport paths, a second one of said routes extending into a second treatment zone aligned with a second one of said transport paths;   (d) at least two payout stands;   (e) at least two takeup stands, a respective one of said payout stands and a respective one of said takeup stands being associated with each of said paths so that a web can be fed along either one of said paths by the payout and takeup stands associated therewith; and   (f) control means for actuating said payout and takeup stands to feed a series of webs along alternate ones of said paths so that each web is fed along one of said paths while the payout and takeup stands associated with another one of said paths are idle, said control means also being operative to coordinate the operation of said directing means to direct said radiant energy into the treatment zone aligned with each of said paths while a web is being fed along such path, whereby each web in the series may be loaded onto an idle payout stand and threaded along the path associated with such stand while another web in the series is being fed along another path and treated by said radiant energy.   
     
     
       2. Apparatus as claimed in claim 1 wherein said emitting means includes means for emitting a beam of radiant energy on a fixed beam path and said means for selectively directing includes an optical element and means for moving said optical element between a first position and a second position so that when said optical element is in said first position the beam will be directed along said first route by said optical element and when said optical element is in said second position the beam will be directed along said second route. 
     
     
       3. Apparatus as claimed in claim 2 wherein said first position is aligned with said fixed beam path and said second position is remote from such path, so that said optical element will intercept said beam when it is in its first position and said optical element will not intercept the beam when it is in its second position. 
     
     
       4. Apparatus as claimed in claim 3 wherein said optical element is a mirror. 
     
     
       5. Apparatus as claimed in claim 4 wherein said means for selectively directing includes a beam splitter and means for moving said beam splitter in coordination with said mirror so that said beam splitter will be aligned with said fixed beam path in front of said mirror when said mirror is in said first position but said beam splitter will be remote from said fixed beam path when said mirror is in said second position. 
     
     
       6. Apparatus as claimed in claim 2 in which said control means is operative to coordinate the operation of said takeup stands with the operation of said beam directing means so that the takeup stand associated with each of said transport paths will accelerate a web extending along such path while said optical element is being moved to the position in which radiant energy will be directed into the treatment zone associated with such path. 
     
     
       7. Apparatus as claimed in claim 1 further comprising means for mechanically threading a web along each one of said paths from a point upstream of the treatment zone associated therewith to a point downstream of such treatment zone. 
     
     
       8. Apparatus as claimed in claim 7 wherein said means for mechanically threading includes a pair of carriers, one such carrier being associated with each of said transport paths, means for engaging the leading end of a web extending from the payout stand associated with each of said transport paths with the carrier associated with such path while such carrier is disposed at the upstream end of such path and means for moving each carrier from the upstream end of the associated path to the downstream end thereof. 
     
     
       9. A method of treating each one of a series of semi-continuous webs with radiant energy comprising the steps of: (a) alternately threading and feeding the webs along two independent transport paths so that each web is threaded along one of the paths while the preceding web of the sequence is being fed along the other one of the paths; and   (b) alternately directing radiant energy at either of two treatment zones, each such treatment zone being aligned with one of said transport paths, so that the radiant energy is directed into the treatment zone aligned with each path while a web is being fed along such path.   
     
     
       10. The method as claimed in claim 9 wherein said radiant energy is emitted from a fixed source, said radiant energy is directed towards one of said treatment zones by positioning an optical element at a first position and said radiant energy is directed towards the other one of said treatment zones by positioning said optical element at a second position different from said first position. 
     
     
       11. The method as claimed in claim 10 wherein said optical element is moved to the position in which radiant energy will be directed towards one of said transport paths while a web which has been previously threaded onto such path is accelerated therealong. 
     
     
       12. A method as claimed in claim 9 wherein each web is fed along one of said treatment paths by a payout stand and a takeup stand associated with such path, further comprising the steps of unloading and reloading the payout and takeup stands associated with each of said transport paths while feeding another web of the sequence along the other one of said transport paths. 
     
     
       13. A method as claimed in claim 9 wherein each web of the sequence is threaded mechanically along one of said paths from a point upstream of the treatment zone associated with such path to a point downstream of such treatment zone.